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Physics beyond the Standard Model at the Energy Fron6er
B. Heinemann UC Berkeley and LBNL
LBNL, January 9th 2013 1
Outline
• Introduc6on • SUSY • Resonances • EWK precision tests
• Conclusions
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Introduc6on
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Proton colliders name years √s [TeV] L
[1034 cm-‐2s-‐1] Int. Lumi [;-‐1]
<μ>
LHC 2015-‐2021 14 1-‐2 300 27
HL-‐LHC 2023-‐2030 14 5 3000 140
HE-‐LHC >2035 26-‐33 2 100-‐300/yr 76
VLHC ? 42-‐100 ? ? ?
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LHC 6meline
LHC Integrated Luminosity
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LHC Parton Luminosi6es
• From √s=7 to √s=14 TeV: • 10 6mes larger cross sec6on for par6cles
• with M~1 TeV for gg collisions • with M~2 TeV for qqbar collisions
• Another factor ~10 increase for √s~33 TeV at ~1 TeV • Larger increases at higher masses 6
Supersymmetry
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Supersymmetry Signatures
1. Inclusive search for jets and missing ET • Probes generic scenarios with squarks and gluinos at ~1 TeV
2. Search for the 3rd genera6on • Probes scenarios where the 1st and 2nd genera6on squarks are much heavier • Mo6vated by naturalness, see M. Papucci’s talk
3. Searches for leptons and missing ET • Probes weakly interac6ng par6cles: partners of W’s, Z’s and leptons • Light gauginos also mo6vated by naturalness
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Current Result: Jets + MET
• Jets result from cascade decays of squarks and gluinos
• Excludes squarks with m<1.5 TeV and gluinos with m<1 TeV • Assuming the squarks are all approximately degenerate
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Jets+MET: Prospects for √s=14 TeV
• With 300/pb exclusion reach approximately doubled: • M(q)~2.7 TeV and M(g)~2.2 TeV • 5σ discovery for M(q)<2.5 TeV and M(g)<2 TeV
• With HL-‐LHC (3/ab) reach further extended by ~0.4 TeV 10
Jets+MET: Prospects for √s=33 TeV
• Reach expected to be up to increase by about a factor 2.4 compared to √s=14 TeV at same L • Mass reach approximately
scales with √s
• Probe squarks and gluinos with M=5-‐6 TeV
• Higher energy much beker than higher luminosity
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3rd genera6on searches
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From L. J. Hall, Berkeley 2011 13
Current Results: Stop quark
• Stop quark search done in many decay channels
• M(stop)<550 GeV excluded for LSP masses below ~150 GeV • Many caveats though as statement depends on other SUSY parameters
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Prospects for √s=14 TeV
• Exclusion reach extended to M~1 TeV • Discovery reach about 0.8-‐0.9 TeV depending on decay
• Improved by 100 GeV for HL-‐LHC compared to LHC
• Probe neutralino masses up to 400 GeV 15
Current Status: mul6leptons+MET
• Limits range between 300 and 600 GeV currently • For LSP masses between 100 and 300 GeV • Depends strongly on slepton mass, most conserva6ve is decays via W/Z
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Leptons+MET: Perspec6ves for √s=14 TeV
• For W/Z decay scenario sensi6vity increased to ~700 GeV for m(LSP)<200 GeV for 300/n • And increased by another ~100 GeV with 3/ab 17
Summary of SUSY Reach
• No evidence for SUSY in current data but much parameter space s6ll unexplored • E.g. limits rather weak for LSP masses of ~300 GeV
• HL-‐LHC increases mass reach by about 20% • But would of course allow exploita6on if SUSY found at current LHC
• HE-‐LHC doubles mass reach approximately • The SUSY Higgs sector is also very interes6ng but no recent studies
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High-‐Mass Resonances
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Z’ decaying to leptons
• Current limits about 2.3 TeV for SM-‐like couplings
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Z’ prospects in dilepton decay
• Sensi6vity in mass will more than double with √s=14 TeV • Another 20% improvement from HL-‐LHC • Another factor ~2 improvement from HE-‐LHC
• Similar for high-‐mass diphoton resonances and ditop resonances • Although in detail will need to be understood if high boosts of top quarks
demand higher granularity trackers etc. 21
Eichten, Hinchliffe, Lane, Quigg 1984
Ditop Resonances
• Predicted e.g. in Randall-‐Sundrum model • Natural scale: several TeV
• Challenging experimentally as top quarks are highly boosted • Studies need further refinement with detailed simula6on to understand
real poten6al • Could challenge detector design (tracker granularity) for HE-‐LHC or VLHC 22
300 ;-‐1 3000 ;-‐1
gKK 4.3 TeV 6.7 TeV
95% exclusion reach:
Top Quark • 50M top quark events in 300/n at LHC! • Allows precision studies in many areas
• Most likely will all be systema6cally limited • Unlikely that precision <1 TeV can be achieved
• ILC measure top mass via threshold scan • Precision: 20 MeV • Measures well-‐defined mass
• Unlike at hadron colliders • Requires √s≈350 GeV
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Other Interes6ng SM tests • Test electroweak couplings between SM gauge bosons
• Test for anomalous decays of top quark • E.g. decay to tZ or γZ • Expected to probe couplings of 10-‐4-‐10-‐5 with 3/ab-‐1
• Test electroweak symmetry breaking via vector boson scakering • Cross sec6on gets regularized by Higgs boson in SM but does this actually happen? • Only possible at hadron collider or mul6-‐TeV lepton collider.
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Vector boson scakering (VBS) • In SM Higgs boson prevents unitarity viola6on of WLWL and ZLZL cross sec6ons • At √s=√(8π<Φ>)=1.2
• Even though Higgs probably has been found s6ll important to measure WW cross sec6on versus √s to see if energy dependence as expected from SM Higgs only (or some new physics is contribu6ng)
New vector boson resonances
• Alterna6ve models of EW symmetry breaking suggest presence of high mass diboson resonances
• Significant improvement with higher luminosity • HE-‐LHC increases rate for m~1 TeV by factor ~5
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Imaginary Scenarios….
• Discover SUSY-‐type signature with gluinos and squarks at 2 TeV and charginos at ~0.4 TeV • HL-‐LHC and/or HE-‐LHC needed to fully explore those par6cles
• HE-‐LHC beker • Out of reach of e+e-‐ machines (if √s≤0.5 TeV)
• Discover sleptons and/or charginos at ~200 GeV • HL-‐LHC will allow measuring them in more detail • ILC with √s>400 GeV can probe them in depth
• Discover stop quark at m~1 TeV but nothing else at 300/n LHC • HL-‐LHC slightly extends mass reach but not greatly • Want HE-‐LHC to see if the rest (or at least more) of the spectrum • Out of reach at ILC (but maybe could modify Higgs couplings?)
• Discover no new par6cles at 300/n LHC • HL-‐LHC moderately interes6ng as increases mass reach • HE-‐LHC very interes6ng as significantly increases mass reach • ILC/Higgs-‐factory/Giga-‐Z could reveal new physics via devia6ons of precision
measurements • …..
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Conclusions on BSM physics
• We have only seen a glimpse of TeV scale physics • Will learn a lot more with 100s of n-‐1 at √s≈14 TeV
• New physics likely has a higher mass scale than we might have hoped: typically >0.5-‐1.0 TeV • If it is at ~2-‐4 TeV the HL-‐LHC will allow much beker exploita6on
(typically improve errors by factor 3) • Given current LHC limits unlikely that a LC with √s≤0.5 TeV can
contribute to directly measuring any new physics par6cles • Indirect constraints through precision measurement are possible op course
• HE-‐LHC and/or VLHC are very interes6ng • In case new par6cles are observed at LHC further higher mass par6cles could well be at higher energies (in reach of higher-‐energy machine)
• In case no new par6cles are observed HE-‐LHC extends mass reach by another fact of two
• A mulJ-‐TeV lepton collider is also very interes6ng • Not as many recent detailed simula6on studies available
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Backup
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VBS reach
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